1. Field of the Invention
This invention relates broadly to devices for disinfection. In a preferred embodiment, the invention relates to devices for disinfection of contact lenses.
2. Description of the Related Art
Contact lenses provide the consumer with an exceptionally convenient and comfortable alternative to conventional eyeglasses. However, proper maintenance of contact lenses involves periodic lens sterilization or disinfection to eliminate harmful bacteria and fungi, and cleaning to remove deposits such as proteins or lipids which adhere to the lens. In order to clean and disinfect contact lenses, a wide variety of devices have been developed.
A particularly efficacious method of disinfecting contact lenses is by a chemical treatment of the lenses with a hydrogen peroxide solution, as described in U.S. Pat. No. 3,912,451, issued to Gaglia, Jr., Oct. 14, 1975. In a typical lens disinfecting apparatus, contact lenses are placed in hydrogen peroxide solution inside a container. The container is sealed (e.g., by threads on the container mating with threads on a cap) for a predetermined period of time to sufficiently disinfect the lenses, with the seal preventing liquid spillage resulting from container movement.
Although hydrogen peroxide is highly effective in disinfecting contact lenses, hydrogen peroxide must be removed from lenses prior to placing the lenses in a patient's eye in order to avoid patient discomfort. One method of removing hydrogen peroxide involves contacting the hydrogen peroxide with a platinum catalyst, thereby rapidly decomposing the hydrogen peroxide into water and gaseous oxygen. Liberated gaseous oxygen resulting from the peroxide decomposition generates internal pressure in the disinfecting container which must be vented. In order to alleviate this pressure, a variety of venting means have been developed. Also, a number of catalytic elements and lens retaining assemblies have been developed. The catalytic elements disclosed in the art have primarily been some form of platinum-coated disk-shaped elements.
For example, U.S. Pat. No. 4,011,941, issued to Parsons on Mar. 15, 1977, discloses a contact lens sterilization container which includes a hollow cylindrical chamber having two opposing openings which are sealed by two caps. One cap includes a convoluted catalytic reactor which is friction-retained on the cap. The catalyst is essentially a disc-shaped element with protuberances extending therefrom. The other cap includes a stem with contact lens holders and a resealable venting means. The venting means is an O-ring positioned in an annular groove passageway from the interior of the container to the exterior surroundings. The O-ring acts as a pressure release valve when oxygen is produced by the decomposition of peroxide in the presence of the catalyst.
U.S. Pat. No. 4,637,919, issued to Ryder, et al., Jan. 20, 1987, discloses a contact lens cleaning container and mating cap, where the cap includes a filter assembly positioned in a vent passageway. The filter assembly includes a hydrophobic membrane which continuously vents the gas generated within the container during the decomposition of peroxide. The pores in the hydrophobic membrane are sufficiently small to inhibit liquid leakage from the container. The catalyst used is the same or analogous to the catalyst disclosed in U.S. Pat. No. 4,011,941.
U.S. Pat. No. 4,750,610, issued to Ryder, Jun. 14, 1988, discloses a disinfecting container which is affixed to a cap via loose threading. The cap includes a resiliently deflectable flange which acts as a check valve in conjunction with the container. In operation, the cap flange is typically in a closed position, i.e., the flange is positioned immediately adjacent a portion of the container, thereby preventing liquid leakage. When excess internal pressure develops, the cap flange deflects, allowing gas to pass through the loosely threaded container-cap connection to the outside of the container. The catalyst used is the same or analogous to the catalyst disclosed in U.S. Pat. No. 4,011,941.
U.S. Pat. No. 4,956,156, issued to Kanner, et al., Sep. 11, 1990, discloses a disinfecting system which includes a cap having a bore. A post is positioned in the bore with a resiliently deflectable diaphragm positioned around the post. The diaphragm-post seal prevents liquid leakage, while allowing gas to pass upon deflection of the diaphragm when sufficient internal pressure develops.
U.S. Pat. No. 4,996,027, issued to Kanner, Feb. 26, 1991, discloses a disinfecting system which includes a container and cap connected by threading. A self-reseating unitary gasket is positioned between the cap and container to provide a liquid-tight seal. Increased internal pressure causes the gasket to unseat, at least partially, allowing gas to pass between the cap and container connection to the environment.
U.S. Pat. No. 5,196,174, issued to Cerola, et al., on Mar. 23, 1993, discloses a structure for removably mounting a catalyst between the contact lenses holders. The catalyst is a disc which is defined as a generally flat, disc-like member with a pattern of recesses and ridges formed on either face or surface thereof. The advantage of the design is that the catalyst may be removed and replaced by a user as the catalytic agent becomes exhausted from use.
U.S. Pat. No. 5,250,266, issued to Kanner, Oct. 5, 1993, discloses a lens disinfecting apparatus, including a container and a cap, in which gas is vented through a type of check valve in the cap. The check valve includes a disc having a linear slit therethrough. The slit generally provides a liquid-impermeable barrier, but when internal pressure is generated, the slit opens to allow gas to pass to the environment.
The previously-described patents describe various alternatives for peroxide-based lens cleaning/disinfecting devices. However, there is a need to provide a less complicated system, both from a manufacturing perspective and from an operational perspective. In addition, there is a need for catalyst elements which are less expensive to manufacture and which provide improved fluid flow profiles during peroxide decomposition. Further, there is a need for improved means for allowing internally generated gas to vent from the disinfection device. There is also a need to improve the cap and lens retaining assembly.